Study On The Failure Mechanism And Impact Intensity Of Accumulated Landslide Based On Particle Flow Code

The study of landslide deformation and failure mechanism and impact intensity is a key content of landslide risk assessment.The mountainous area of southern Shaanxi is a high risk area of landslide disaster in our country.There are a large number of landslides in accumulation layer,which seriously threaten the safety of people's life and property and the sustainable development of social economy.The formation,deformation and failure mechanism of this type of landslide and the quantitative study of landslide impact intensity have important theoretical and practical significance for the quantitative evaluation of landslide risk and landslide disaster prevention and mitigation.Based on the analysis of the landslide deformation failure mechanism,landslide impact intensity and the present research situation of accumulation layer landslide at home and abroad,this paper takes the Yangjiawan accumulation layer landslide in Mian county,southern Shaanxi mountain area,as the research object.Through field investigation,survey and laboratory experiments,the geological environment conditions,landslide development characteristics,landslide influencing factors and their stability in landslide area are studied.It is showed that Yangjiawan landslide is a shallow expansive accumulation layer landslide.The main influencing factors are stratigraphic lithology,rain,earthquake and human engineering activities.The landslide is unstable in the condition of saturated water.Based on the analysis of geological characteristics of landslide,based on particle flow method and constitutive model theory of rock and soil,the numerical model of Yangjiawan landslide is constructed,and the deformation failure mechanism and movement characteristics of landslide are studied deeply.It is considered that the deformation failure mechanism of the landslide is typical traction progressive failure.Based on the analysis of landslide movement characteristics,the landslide impact intensity index,such as impact force,impact distance,impact velocity and kinetic energy,are selected to characterize the landslide impact intensity.The quantitative study of landslide impact int is carried out,and the theory of energy conservation is combined.The theoretical calculation formulas of landslide impact force and impact velocity are derived,and the comparative analysis of landslide impact intensity index is carried out.It is concluded that the landslide impact force decreases linearly with the increase of slope foot distance.The impact velocity and kinetic energy of landslide first increase rapidly and then decrease slowly,and the numerical analysis results of the variation characteristics of correlation strength index are in good agreement with the theoretical calculation results.The related research methods and results provide the necessary reference for the quantitative assessment of landslide risk,especially for the quantitative analysis of vulnerability of the bearing body.